The background description provided herein is for the purpose of generally presenting the context of the disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Energy scavenging from an ambient source such as a photovoltaic cell (PV), a radio frequency (RF) device, a thermoelectric generator (TEG), or a piezoelectric material (such as lead zirconate titanate) is particularly suited for use in IoT (Internet of Things) products and applications. The Internet of Things (IoT) is the network of physical objects or “things” embedded with electronics, software, sensors, and network connectivity, which enables these objects to collect and exchange data. The Internet of Things allows objects to be sensed and controlled remotely across existing network infrastructure, creating opportunities for more direct integration between the physical world and computer-based systems, and resulting in improved efficiency, accuracy and economic benefit. Each thing is uniquely identifiable through its embedded computing system but is able to interoperate within the existing Internet infrastructure. Energy scavenging may be utilized in an IoT application where on-line utility power is not reachable and an off-line stand-alone battery does not fit due to constrains in size and/or weight.
An energy harvesting source may have power characteristics different from a traditional power supply. For instance, total power available may be capped and/or the amount of power may depend on internal I-V characteristics rather than a load demand as the case in other power supplies. Maximizing power output from an energy harvesting source may involve constantly directly measuring the power at the output of the energy harvesting sources. These direct measurements may utilize current sensing (which may result in power losses), may utilize components that significantly contribute to physical dimensions of an electronic device (such as volume or area of the electronic device), and/or may utilize components that increase production costs, such as a bill of materials (BOM) cost.